Spatially resolved nuclear spin relaxation, electron spin relaxation and light absorption in swift heavy ion irradiated LiF crystals

摘要

Spatially resolved ~19F and ~7 Li spin-lattice relaxation rates are measured for LiF single crystals after irradiation with two kinds of swift heavy ions (~12C of 133MeV and ~208Pb of 1.78GeV incident energy). Like in earlier studies on ~130Xe and ~238U irradiated LiF crystals, we found a strong enhancement of the nuclear spin-lattice relaxation rate within the ion penetration depth and a slight - but still significant - enhancement beyond. By evaluating the nuclear relaxation rate enhancement within the ion range after irradiation with different projectiles, a universal relationship between the spin-lattice relaxation rate and the dose is deduced. The results of accompanying X-band electron paramagnetic resonance relaxation measurements and optical absorption spectroscopy are included in a physical interpretation of this relationship. Also the reason for the enhanced relaxation rate beyond the ion range is further discussed.